Which one of the following pairs is correctly matched?

Options

A. Rhizobium - Parasite in the roots of leguminous plants
B. Mycorrhizae- Mineral uptake from soil
C. Yeast - Production of biogas
D. Azospirillum - Symbiotic `N_(2)`- fixing bacterium

Explanation

To determine which pair is correctly matched from the given options, we will analyze each option step by step.

### Step-by-Step Solution:

1. **Examine Option 1: Rhizobium and Leguminous Plants**
- The option states that Rhizobium is a parasite in the roots of leguminous plants.
- **Analysis**: This is incorrect. Rhizobium is not a parasite; it forms a symbiotic relationship with leguminous plants, where it fixes nitrogen for the plant in exchange for carbohydrates.
- **Conclusion**: This option is incorrect.

2. **Examine Option 2: Mycorrhiza and Mineral Uptake**
- The option states that mycorrhiza helps in mineral uptake from the soil.
- **Analysis**: This is correct. Mycorrhizae are symbiotic associations between fungi and plant roots. The fungi enhance the plant's ability to absorb water and minerals from the soil, while the plant provides carbohydrates to the fungi.
- **Conclusion**: This option is correct.

3. **Examine Option 3: Yeast and Biogas Production**
- The option states that yeast helps in the production of biogas.
- **Analysis**: This is incorrect. Yeast is primarily used in the fermentation process to produce alcohol, not biogas. Biogas is produced by anaerobic bacteria, particularly methanogenic bacteria.
- **Conclusion**: This option is incorrect.

4. **Examine Option 4: Azospirillum and Nitrogen Fixation**
- The option states that Azospirillum is a symbiotic nitrogen-fixing bacterium.
- **Analysis**: This is incorrect. Azospirillum is a free-living nitrogen-fixing bacterium, not a symbiotic one. It can associate with plant roots but does not form the same type of symbiotic relationship as Rhizobium does with legumes.
- **Conclusion**: This option is incorrect.

### Final Answer:
The only correctly matched pair is **Option 2: Mycorrhiza helps in mineral uptake from soil**.

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